ZnVO3: an ilmenite-type vanadium oxide hosting robust V–V dimers

Abstract

Ilmenite-type vanadium oxides exhibit a distinctive cation-dimerization behavior. Here, we report a novel ilmenite-type compound, ZnVO₃. Polycrystalline ZnVO₃ samples are synthesized under conditions of 10 GPa and 1573 K. The obtained sample crystallizes in the triclinic P space group. Both V–V and Zn–Zn dimers (dimer-like displacement) are present in the structure, arranged in a ladder-like pattern on each honeycomb lattice. Notably, the V–V dimer persists up to 625 K, surpassing the stability of the V–V dimer state in other ilmenite-type vanadium oxides. Magnetic susceptibility measurements corroborate the formation of direct V–V bond in the dimer. The off-centered position of the Zn²⁺ ion at the octahedral site, driven by Zn–O covalency and its sp³ nature, promotes the Zn–Zn dimer-like displacement. Cooperative distortions between honeycomb layers further reinforce the V–V dimers. This finding offers insights into controlling cation-dimer strength in crystalline compounds via crystal structure distortions.